A. Field of the Invention
The present invention relates to scientific data processing systems. More particularly it relates to those scientific vector data processing systems which require high speed access to scalar variables, parameters, temporary operands and register save areas in the data processing system. A local store is disclosed which serves as an internally available portion of the main store associated with the task which is currently active on the scientific vector processor. The content of the local store is moved from the main store upon initiation of the task start-up sequence. Thereafter, the local store provides programmer transparent high speed access with no main store delays for high use constants or scratch-pad operations. The content of the local store is returned to the main store upon task completion or upon exit from the scientific vector processor.
B. Prior Art
Past attempts to overcome the delay caused by access to the main memory of a data processing system have been directed to the use of either special purpose memories or cache memories. These were often small high speed memories which usually had to be used separately by the programmer. Further, since they were of a fixed size, care had to be taken by the programmer to ensure that the memory did not overflow.
In previous architectural approaches, these small, high speed memories were usually accessible only to a particular portion of the system. In fact, in most instances, they were accessible only to the arithmetic logic unit of the data processing system. They were used to store information which needed to be accessed often and quickly by the ALU. The information stored there was so specified by the programmer and much attention was needed by him to be sure that such information was brought from the main memory to the small high speed memory prior to its need by the ALU.
Other increases in computing rates have been achieved through advances in physical technologies relating to software and hardware functioning. The advent of integrated circuitry gave rise to circuit components operable at very fast computing rates, and capable of performing complex functions while remaining economically feasible. Access and cycle time of memories has also been markedly decreased.
In addition to the changes and developments in the hardware, there have been continuing advances in the organizational architecture of data processing systems that provide for ever-increasing utilization of the various data processing components. While many examples of optimization of utilization of the components comprising the data processing systems can be described, attention will be directed to the concept of increasing data processing rates by providing for a local store having single cycle access time.
This invention addresses the need for a unique high speed local store apparatus which provides fast access by various portions of the processor to the information stored therein.